4 ms·

theoretically, are there any regulatory issues on a piece of aluminum sold (and marketed) for this purpose? if not, why aren't there cheap and effective such d

theoretically, are there any regulatory issues on a piece of aluminum sold (and marketed) for this purpose? if not, why aren't there cheap and effective such designs on alibaba - why have to DIY?

ars 9y ago
No regulatory issues. The aluminum acts to increase the antenna gain (i.e. concentrate the signal in a particular direction). The total power does not increase instead you take some from one place and add it to another. There are tons of products for sale. You can get a replacement antenna that is a directional dish for example, instead of the typical omnidirectional dipole (stick).
- cesarb 9y ago
  > No regulatory issues. The aluminum acts to increase the antenna gain (i.e. concentrate the signal in a particular direction). AFAIK, many countries limit the EIRP, which increases with the antenna gain.
  - tzs 9y ago
    Correct. In the US, for example, for 2.4 GHz point-to-multipoint, EIRP is limited to 4 watts, and maximum power to the antenna is limited to 1 watt. So, if your router does 1 watt, you are limited to a maximum 6 dBi antenna gain. Lower the router power, and you can use higher gain antennas. It's more complicated for 2.4 GHz point-to-point. At 1 watt transmitter power you are allowed a 6 dBi antenna. But for every 1 dBi you reduce transmitter power, you are allowed an additional 3 dBI of antenna gain to a maximum of 30 dBi antenna gain at 160 mW transmitter power. 5 GHz has even more complicated rules, I believe. See: https://www.air802.com/fcc-rules-and-regulations.html https://www.air802.com/fcc-rules-and-regulations.html
    - vvanders 9y ago
      Or if you get your ham license you have a limit of 1500W PEP[1], just plug your callsign into the router ID and away you go. However that means you're also subject to no encryption or business related traffic. [1] http://www.qsl.net/kb9mwr/projects/wireless/allocations.html http://www.qsl.net/kb9mwr/projects/wireless/allocations.html
      - logicallee 9y ago
        >However that means you're also subject to no encryption or business related traffic. how does that work? isn't all wifi traffic encrypted by something between devices and AP? (I skimmed your link and did a find for encry on it but saw nothing.)
        cesarb 9y ago
        No, encryption is an optional feature of the 802.11 standards. Every once in a while I see an unencrypted wifi AP nearby (it's the default on Android to show a notification whenever it sees an unencrypted wifi AP).
    - walshemj 9y ago
      I think 4W that is for professional ptp use only.
- logicallee 9y ago
  This was interesting, thank you. Given that we're literally talking about a piece of aluminum foil, I'm surprised this isn't more common.
- deleted 9y ago
  [deleted]

theoretically, are there any regulatory issues on a piece of aluminum sold (and marketed) for this purpose? if not, why aren't there cheap and effective such designs on alibaba - why have to DIY?

ars 9y ago

No regulatory issues. The aluminum acts to increase the antenna gain (i.e. concentrate the signal in a particular direction). The total power does not increase instead you take some from one place and add it to another. There are tons of products for sale. You can get a replacement antenna that is a directional dish for example, instead of the typical omnidirectional dipole (stick).

cesarb 9y ago
> No regulatory issues. The aluminum acts to increase the antenna gain (i.e. concentrate the signal in a particular direction). AFAIK, many countries limit the EIRP, which increases with the antenna gain.
- tzs 9y ago
  Correct. In the US, for example, for 2.4 GHz point-to-multipoint, EIRP is limited to 4 watts, and maximum power to the antenna is limited to 1 watt. So, if your router does 1 watt, you are limited to a maximum 6 dBi antenna gain. Lower the router power, and you can use higher gain antennas. It's more complicated for 2.4 GHz point-to-point. At 1 watt transmitter power you are allowed a 6 dBi antenna. But for every 1 dBi you reduce transmitter power, you are allowed an additional 3 dBI of antenna gain to a maximum of 30 dBi antenna gain at 160 mW transmitter power. 5 GHz has even more complicated rules, I believe. See: https://www.air802.com/fcc-rules-and-regulations.html https://www.air802.com/fcc-rules-and-regulations.html
  - vvanders 9y ago
    Or if you get your ham license you have a limit of 1500W PEP[1], just plug your callsign into the router ID and away you go. However that means you're also subject to no encryption or business related traffic. [1] http://www.qsl.net/kb9mwr/projects/wireless/allocations.html http://www.qsl.net/kb9mwr/projects/wireless/allocations.html
    - logicallee 9y ago
      >However that means you're also subject to no encryption or business related traffic. how does that work? isn't all wifi traffic encrypted by something between devices and AP? (I skimmed your link and did a find for encry on it but saw nothing.)
      - cesarb 9y ago
        No, encryption is an optional feature of the 802.11 standards. Every once in a while I see an unencrypted wifi AP nearby (it's the default on Android to show a notification whenever it sees an unencrypted wifi AP).
  - walshemj 9y ago
    I think 4W that is for professional ptp use only.
logicallee 9y ago
This was interesting, thank you. Given that we're literally talking about a piece of aluminum foil, I'm surprised this isn't more common.
deleted 9y ago
[deleted]